Fuel metering system for internal combustion engines

In a fuel metering system, for use with an internal combustion engine, the system including:

• A. an air induction tube containing a throttle valve;
• B. an exhaust pipe;
• C. a fuel container connected by an air conduit with the induction tube of the engine;
• D. sensor means, for determining the chemical composition of the exhaust gas of the engine and providing an output signal;
• and
• E. valve means, located in said air conduit, for changing the effective flow cross section thereof and controlled by the output signal from said sensor means;
• the improvement in the fuel metering system comprising:
• F. an electric heating element mounted on at least a portion of the upstream surface of the throttle valve in the induction tube for supplying heat thereto to vaporize fuel droplets condensed on said upstream surface;
• and
• G. heating means located adjacent and upstream of the throttle valve, for heating up a portion of the interior wall of the induction tube in the immediate region of the heating means, said electric heating element and said heating means cooperating to prevent the condensation of fuel on the surface of the throttle valve and on the interior walls of the induction tube region lying immediately upstream of the throttle valve.